rtl8xxxu: Stop log spam from each successful interrupt

As soon as debugging is turned on, the logs are filled with messages
reporting the interrupt status. As this quantity is usually zero, this
output is not needed. In fact, there will be a report if the status is
not zero, thus the debug line in question could probably be deleted.
Rather than taking that action, I have changed it to only be printed
when the newly added RTL8XXXU_DEBUG_INTERRUPT bit is set in the debug
mask.

Signed-off-by: Larry Finger <[e-mail]>
Signed-off-by: Jes Sorensen <[e-mail]>
Signed-off-by: Kalle Valo <[e-mail]>

drivers/net/wireless/realtek/rtl8xxxu/rtl8xxxu.h

···
 #define RTL8XXXU_DEBUG_H2C		0x800
 #define RTL8XXXU_DEBUG_ACTION		0x1000
 #define RTL8XXXU_DEBUG_EFUSE		0x2000
+#define RTL8XXXU_DEBUG_INTERRUPT	0x4000
 
 #define RTW_USB_CONTROL_MSG_TIMEOUT	500
 #define RTL8XXXU_MAX_REG_POLL		500

drivers/net/wireless/realtek/rtl8xxxu/rtl8xxxu_core.c

···
 	struct device *dev = &priv->udev->dev;
 	int ret;
 
-	dev_dbg(dev, "%s: status %i\n", __func__, urb->status);
+	if (rtl8xxxu_debug & RTL8XXXU_DEBUG_INTERRUPT)
+		dev_dbg(dev, "%s: status %i\n", __func__, urb->status);
 	if (urb->status == 0) {
 		usb_anchor_urb(urb, &priv->int_anchor);
 		ret = usb_submit_urb(urb, GFP_ATOMIC);